Dick Clark, renowned as "America's oldest teen-ager," has diabetes.

Clark, 74, has had type 2 diabetes, formerly called adult-onset diabetes, since 1994, but he kept it a secret from everyone except close friends and family, according to the Ogilvy public relations firm, which is promoting his new role as a spokesman for the American Association of Diabetes Educators and pharmaceutical maker Merck & Co.

Word of his illness was first reported in a gossip column in the New York Daily News.

Clark, the former host of American Bandstand, is working with the firms to launch "Diabetes: Know the Heart Part," a national public education campaign to alert Americans to the link between diabetes and heart attack and stroke.